Portable audiphone transmitter



Dec. 19, 1922.

1,439,212. 0, E. WILLIAMS.

PORTABLE AUDITPHONE TRANSMITTER.

FILED NOV-5, 1920.

Patented Dec. 19, 1922.

PATENT OFFICE.

CHARLES E. WILLIAMS, OF CHICAGO, ILLINOIS.

PORTABLE AUDIPHONE TRANSMITTER.

Application filed November 5, 1920. Serial No. 421,880.

T all whom it may concern.

Be it known that I, C-I-IAnLns E. WILLIAMS, a citizen of the United States, and a resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Portable Audiphone Transmitters, of which the following is a full. clear, and exact specification. such as will enable others skilled in the art to make 1 and use the same.

My present invention relates to improvements in sound modifiers, and has special reference to a sound modifier operable in connection with a type of sound transmitter which depends for its operation upon the fact that the change of pressure upon a carbon contact element for transmitting electric current changes the conductivity of the carbon element and the current transmitted thereby. In such transmitting devices, the character of the sound produced depends conjointly upon the character of the carbon element and the character of the diaphragm which modifies the compression of the carbon as well as upon the character of the reverberatory chamber, and, as is Well known, the control of the character of the transmitted sound, being thus dependent upon the character of its respective elements, is extremely difficult. I have discovered that by controlling the sound which operates upon the transmitter elements, I can control the sound which is transmitted or produced bythem.

My present invention is particularly applicable to portable audiphones or hearing devices for use by persons afllicted with partial deafness, and my improvements, generally stated, consist in the placement of a 0 supplementary or auxiliary diaphragm in front of the usual transmitter elements so as to form one of the walls of the air-tight or substantially air-ti ht reverberatory chamber. By changing t e character of this auxiliary diaphragm I am also able to modulate the pitch of the instrument and thus adjust it for different persons as well as permit the hearing of sounds coming from a greater distance. Also I am able by means of this auxiliary diaphra m to eliminate to a large extent the rattl ng sound of the globules in the carbon element, which of course clarifies the produced sound and to a certain extent amplifies the same and renders the human voice more natural to the hearer.

The objects of present invention are the provision of simple means for modifying or controlling the sound produced by a transmitter; the designing of "a structure for such a purpose which has but few parts and may be manufactured and marketed at a relatively economical price; and the production of a device that-is dependable in performing the functions for which it has been designed. I prefer to carry out my invention by means of a structure substantially as illustrated in the accompanying draw-' ings, in which- Figure 1 is a transverse section schematically illustrating a form of sound transmitter with my modifying device applied thereto.

Figure 2 is a sectional view on line 2-2 of Figure 1 of the drawings.

Figure 3 is a View similar to Figure 1 of a modifiedstructure.

The transmitter proper is mounted upon a plate 5 which is centrally dished at 6. The dished portion is perforated in any desired pattern with apertures 7 and to the central portion of the dished area is secured, by means of the screw 8 and nut 9,

a carbon element 10. The carbon element.

is insulated from the dished part 6 by suitable insulation preferably a fiber disk 11 interposed between the parts. Mounted directly back of the dished portion 6 upon plate 5 is an interiorly threaded annulus 12 having an inwardly extended lateral flange or shoulder 13 upon which seats 2. diaphragm 14, which is secured therein by the threaded ring or-bezel 15. Suitable packing 16. may be employed to prevent diaphragm 14 moving with respect to) its mounting. Plate 5 is mounted upon a box phragm may be formed of'carbon, metal, parchment, or wood, depending upon the character of the modification or modulation which it is desired to secure in the promodifying or tone modulating diaphragm 21. Such. modifying (11a '17 which encloses the transmitting elements.

' or less quantities of wax or shellac, or any other suitable substance which will affect their elasticity and vibratory qualities.

It will be seen that the space between diaphragms 21 and 14: constitute an enclosed chamber, the pulsations of the air in which are received from and controlled by the vibration of supplementary diaphragm 21. In order to. allow diaphragm 14 to vibrate more freely from the impulses received from diaphragm 21, I have provided vents 22 between the edges of plate 5 and its juncture with the lateral wall 23 of closure 18, the front wall of said closure being extended at its edges 24 in front of these openings 22.

The electrical terminal posts 26 are mounted in an insulating block 27 secured preferably at the bottom edge of plate 5 outside the reverberatory chamber, one of said terminals being connected through an insulated conductor 28 with the central carbon element 10, while the other terminal post is connected through an insulated conductor 29 with annulus 12.

My invention may also be employed in the modified structure shown in Figure 3, in

which a cup-shaped casing 30 is employed having perforaltio1ns'31 in lone end wall. Opposite the perforated wall and upon an annulus 32 is mounted a supplementary sound modifying or tone and pitch modulator diaphragm 33. Behind the diaphragm 33 a bridge-member oI bracket 34 is mounted to which the carbon element 35 is secured in any desired or Well known manner such as a bolt and nut as shown. The carboncontacting diaphragm 36 is mounted within casing 30 by means of an annulus 37, or in any other suitable way, and the back or rear portion of casing 30 is closed by any suitable closure or plate 38. While the details of these structures differ slightly from that shown in Figures 1 and 2 the principles in-,

volved are identical. I I

While I have shown herein but two types of structures in which my invention is applicable it will of course be obvious to others skilled in this art that divers other modifications or refinements of the herein-disclosed device are possible. Therefore I Wish it understood that I do not limit myself to the precise application and principles shown and described, as such changes are fully contemplated as coming within the scope of the appended claims.

Having described my invention, what I claim is:

1. In combination with a sound transmitter comprising a carbon element and a resonant vibratory element for modifying the density of said carbon element, of a casing enclosing the aforesaid structure adjacent and opposite the rear wall of which said resonant vibratory element faces, the front wall of said casing being provided with sound entrant ports or apertures, and an auxiliary resonant element or diaphragm mounted on the back of the front of said casing opposite said sound entrant ports.

2. The combination with a. sound transmitter comprising a carbon element of two resonant vibratory elements between which .said carbon element is disposed and with perforations upon said front wall, a bridging element extending across said casing, a carbon element mounted upon said bridging, and a second resonant vibratory element mounted behind said bridging and associated with said carbon element so that the movement of said second vibratory element will vary the density of said carbon "element.

Signed at Chicago, county of Cook and State of Illinois, this 2d day of November, 

